Does the use of secular humanism textbooks violate the Establishment Clause?

Similarly, in Smith v. Board of School Commissioners of Mobile County, 827 F.2d 684 (11th Cir.1987), plaintiffs challenged a school's use of textbooks that they characterized as endorsing the religion of secular humanism. The court observed that the textbooks contained ideas that were consistent with the tenets of secular humanism. It nevertheless concluded that the textbooks did not violate the Establishment Clause because "mere consistency with religious tenets is insufficient to constitute unconstitutional advancement of religion." Id. at 692.